Atmospheric pressure responsive device



Dec. 17, 1940; H. HEINRICH ErAl.

ATMOSPHERIC PRESSURE RESPQNSIVE DEVICE Filed June 9, 1937 .72? van for:

Patented Dec. 17, 1940 UNITED STATES PATENT OFFICE- ATMOSPHERIC PRESSURE RESPONSIVE DEVICE tion of Germany Application June 9, 1937, Serial No. 147,330 In Germany May 18, 1936 4 Claims. (c 137-1565) devices can be easily injured by the vibrations occurring in the operation of the engine. These vibrations affect the exactitude of the control and cause bending stresses at the fastening points of the capsules which greatly reduce the strength and durability of the device.

These drawbacks are avoided according to the invention by the adjusting member acting on the fuel feed consisting of severaldiaphragm capsules, each guided so as to be longitudinally displaceable. By this means the further substantial advantage is obtained, that a large adjusting movement that is equal in length or extent to the sum of the movements exerted by the individual diaphragm capsules is available for influencing the fuel feed. The controlling device can thus, by means of the invention, be arranged in a comparatively small space without a power amplifier operated from an external auxiliary source of power, for instance oil under pressure, having to be employed to obtain the desired extent of movement.

A further substantial advantage consists in the feature that if a leakage occurs only one diaphragm capsule becomes inoperative. The small irregularity in the working of the appartus thereby occurring can be easily compensated for, and the internal combustion engine can be kept in further operation until the defective diaphragm capsule can be changed on the occasion of a longer stoppage of the vehicle. Preferably, the diaphragm capsules are mounted so as to be longitudinally displaceable loosely within a common guide, and operativelyconnected together or held in place by a spring which acts at the same time as a return force. In view of the fact that the capsules are usually made of very thin metal and are subjected in use to considerable vibration and bending stresses, guide means are providedto support and guide the capsules and to protect them against wear.

In the accompanying drawing- Fig. 1 is a sectional view of an example of construction of the invention, and

Fig. 2 shows a somewhat different construction of the diaphragm capsules shown in Fig. 1.

A cylindrical sleeve l I bounded by walls l2 and I3 is arranged in a casing Ill, in which sleeve four diaphragm capsules l5 are mounted so as to be longitudinally displaceable. These are operatively connected together and to the wall l2 by a' spring I! by the intermediary of a lever IS. The lever i6 is pivotally mounted in two supports 18 provided on the sleeve l I, and carries at its lower angularly bent and forked end the fulcrum iii of a two-armed lever 20, which is carried through two slots M in the sleeve l l. This lever has a cranked part for the spring l1, and is connected by its upper end to a link 2| pivotally mounted on the controlling member 22 of an injection pump of known type, while the other lever arm, made forked and provided with a guide slot 23, engages with a driving member 24 that is provided on'a bolt 26 connected to a diaphragm 25.

The diaphragm 25 and the bolt 26with a spring 21 serving for the guidance of the bolt, are arranged in a casing member 30 flanged on to casing l0 and in open communication with it, and provided with a cover 3| shutting off the diaphragm. In the hollow interior of this cover two springs 28 and 28' serving as return force springs are arranged. A pipe for the ofitake of pressure leading to the air induction pipe of the internal combustion engine'is connected to a pipe-connection 29.

The sleeve l I enclosing the diaphragm capsules is mounted in the casing l0 so as to be displaceable, so as to be able to vary the adjustment of the controlling rod 22, if required, independently of the action of the diaphragms l5 and 25. For this purpose, a lever 33 having a guide slot is employed, which is secured to a shaft 34 passing through the casing l0 and provided with an adjusting lever 35. Lever 33 acts on a bolt 32 provided on the wall l2 of the sleeve II, and the freedom of movement of this lever is limited by a stop-pin 36. The casing H) can be connected by a face to an injection pump of known type, having a controlling member, indicated by 22, which controls the injection amount. Instead of the cylindrical sleeve, a cage consisting of separate guide-bars may also be employed.

The mode of working of the apparatus is as follows:

If the air supply to the engine is throttled, a vacuum occurs in .thepressure feed pipe connected to the pipe socket 29, and thusalso in the interior of the cover 3|. The diaphragm 25 is in this case forced into the interior of the cover by atmospheric pressure until the springs 28 and 28' have compensated for the difference in pressure acting on the diaphragm and the opposing force of the spring 21. By this movement the lever 20 5 is rocked about the axis I 9 and the controlling rod 22 pulled into a position in which the feed of fuel is reduced. When the external air pressure sinks, the diaphragm capsules expand and move the fulcrum 19 to the left. In this case also the lever-20 and thus also the controlling rod22 are brought into a position reducing the feed of fuel. In order to adopt the particular amount of fuel delivered to the fuel requirement of the engine, the abutments of the springs 11, 21 and 28' are arranged so as to be adjustable. I

Of course, a controlling of the mixture dependent on the changing working conditions may also be obtained by a throttle valve arranged in the air induction pipe being movably connected to the lever 20, and this lever in case' of need, furthermore can act on a controlling member governing the fuel feed and thus corresponding to the controlling rod 22.

The diaphragm capsules shown in 'Fig. 2 differ from those in Fig. 1, simply by the feature that a threaded bolt 4| and a nut 42 by which the capsules can be connected together are respectively secured to their elastic flexible walls. Centering rims 43 are provided on the nuts on which guide-plates 44 provided with a corresponding bore are placed, the edges 45 of which plates overlap the diaphragm capsules. These guide-plates are gripped, when each two adjacent diaphragm capsules are assembled, between the shoulder formed in making the centering rim and the foot of the threaded bolt.

When assembled, the guide plates 44 are arranged between the capsules l5 andextend over the edges thereof to support and guide them in sleeve II and also to protect them against wear due to vibration and relative movement between these parts, This is important, particularly when the capsules are made of relatively thin metal because, in use, these parts are subjected to con- 45 siderable vibration and bending stresses. We declare that what we claim is: 1. In apparatus of the character described, an atmospheric pressure responsive device comprising a casing, a plurality of diaphragm capsules 50 sensitive to variations in atmospheric pressure mounted in series in said casing for longitudinal movement therein, each of said capsules bein provided with guiding means arranged between adjacent capsules and projecting over the edges 55 of its respective capsule, said guiding means heeach capsule being provided with guiding means carried by said connecting means and projecting over the edges of its respective capsule, said guiding means being capable of being moved axially together with its respective capsule within the common casing, whereby contact of the edges of said capsule with said casing is prevented.

3. An atmospheric pressure responsive device comprising a casing, a plurality of diaphragm capsules influenced by variations in atmospheric,

pressure mounted in'series for longitudinal displacement in said casing, connecting members for connecting. together adjacent capsules, a centering rim being provided on one of each pair of connecting members, and a guide member for each capsule mounted on the centering rim and held in position thereby, each guide member projecting over the edges of its respective capsule and being movable with its respective capsule within the casing whereby said capsules are centrally supported and guided for longitudinal displacement in said casing and contact of the edges of said capsules with said. casing is prevented.

4. An atmospheric pressure responsive device comprising a casing, a plurality of diaphragm capsules influenced by variations in atmospheric pressure mounted. in series for longitudinal displacement in said casing, means for connecting together adjacent capsules whereby the expansion and contraction movements. of the capsules are translated from one capsule to the other and guidemembers one for each capsule carried by said connecting means and movable with its respective capsule within the common casing for supporting and guiding said capsules in said casing, said guide members each comprising a disc having an edge at right angles thereto which at least partly encloses its respective capsule and prevents contact of the edges of the capsule with said casing.

HANS HEINRICH. ALFRED SCHWEIZER. 

